Rail flash welder



Dec. 1, 1942.

G. L. JONES RAIL FLASH WELDER Filed Aug. 19, 1941 INVENTOR BY Gkafim"[Ears/e JO-IVEJ W I ATTORNE Patented Dec. 1, 1942 RAIL FLASH WELDERGeorge Lester Jones, Garden City, N. Y., assignor to Sperry Products,Inc., Hoboken, N. .L, a corporatlon of New York Application August 19,1941, Serial No. 407,392

3 Claims.

leading mute the fixed part of the machine,

and clamping the following rail to the moving platen. The platen is thenmoved at a predetermined low speed until the ends of the adjacent railsengage and for a predetermined dislance thereafter, that is, until acertain amount of rail has been burned 01f. At this point, the speed ofthe platen is increased to cause burnolf at a higher rate and finallythere is a further sudden increase in the speed of movement of theplaten for the pushup. The first increase in speed, as well as the finalincrease or push-up, is determined by means of limit switches on thefixed part of the machine with which the moving platen is adapted toengage as it travels toward the fixed rail.

When the weld has been completed, the platen is withdrawn, and thestring of welded rail is drawn out of the machine until the rear end ofthe last rail is in welding position. Then the next rail is run inacross the platen until it is near the rear end of the welded string.Be-

, cause of the inertia of the rail moving into the welding machine, itis not possible always to stop the new rail in the same predeterminedposition with respect to the platen. As stated 1 above, when the platenbegins to move forward at its first speed, it moves a predetermineddistance until it engages the limit switch for the first increasedspeed. It will be seen that part of this predetermined distance consistsin bringing the rails in contact, and that the remaining part of thisdistance consists in the heating up and burning off of the rail endswhich are now in flashing engagement. The total distance moved by theplaten until itengages the first increased speed limit switch isconstant. and, therefore, it will be seen that unless the leading end ofthe new rail is in the same constant initial position with respect tothe platen every time;

and unless the rear end of the preceding rail is in the same constantinitial position with respect to the fixed part of the machine everytime, it will result in the adjacent ends of the rails to be weldedmaking engagement sooner or later-than the desired time of engagement.and

due either to insufllcient heating up of the ends because the limitswitch has been reached too soon, or in excessive burn-off of materialbecause the limit switch has been reached later than the predeterminedtime after the ends have engaged.

The problem which is set forth above, could be avoided if it werepossible to have the ad- ,acent ends of the rails spaced apart the sameamount each time, in other words, if the new rail being fed into themachine could have its leading end' stopped always at a fixed distancenom the rear end of the welded string, then this problem would not arisebecause the total distance traversed by the platen being constant, andthe distance between adjacent rail ends be ing constant, there would bea constant amount or burn-oil of the ends of the rail by the time theplaten reached the limit switch. This is possible where the objects tobe welded are light in weight and can be readily stopped intheirprogress by ordinary mechanical stops. In the case of heavy objects,however, such as rails, the great mass of the welded string, as well asthe great mass of the incoming rail, is such that the momentum makes itimpossible etfectively to stop either of these members by ordinarymechanical stops. Therefore, the stopping points, both of the rear endof the welded string and the forward end of the new rail are indefinite,and the distance between these adjacent ends will vary, thus creatingthe problem set forth above. v

The principal object of my invention, therefore, is to provide meanswhich will insure bumoll of a constant amount of the adiacent rail ends,before the first limit switch is encountered by the moving platen sothat uniform welds will be obtained, regardless of the relative positionof the adjacent rail ends before platen move ment began. For thispurpose, I provide means for controlling the actuation of the limitswitches, and particularly of the first limit switch, not by the totalmovement of the platen ment creates large momentum forces making itdifficult to employ ordinary mechanical stops. The machine disclosed isa rail flash welding machine of the type disclosed in my joint patentwith Charles B. Roeds, No. 2,250,869, granted July 29, 1941. Thismachine comprises the fixed portion in upon which is mounted a movableplaten II. The platen may be supported upon guide bars 12 on the fixedportion with which engage arms l3 carried by the platen. The platen isthus mounted for reciprocatory movement, and such movement may beeffected in any manner, as, for instance, as disclosed in the saidpatent which includes a plunger I5 fixed to the platen, and adapted tobe actuated by fiuid pressure, such as hydraulic pressure, operatingfrom a suitable source. The rail R may be the first rail which has beeninserted in the machine, or it may be the last rail of a long stringwhich has already been welded. In any case,-the rear end I9 of the railR is held'upon the fixed base I of the machine by suitable clamps, suchas side clamps (not shown), which hold the rail fixed laterally, and bytop clamp 22 which is held in engagement with the tread portion 23 ofthe rail by suitable pressure means, such as the hydraulic pressuremeans shown in the said patent. Similarly, after the rail R has been fedinto the machine until its leading end lies adjacent the rear end I 9 ofrail R, the said rail R is clamped to the platen H by a clamp 22'similar to clamp 22 and similarly held down in engagement withthe railtread 23. Suitable side clamps (not shown) are also employed. When therails have been clamped in position on the fixed base In and on themovable platen il, respectively, current clamps 25 and 25 are applied tothe respective rail ends for leading current into these rails from atransformer. The primary winding of the transformer is energized from asuitable source, and the secondary winding is connected by the leads 26and 21 to the current clamps 25 and 25'.

The platen II is now fed forward at a predetermined rate. This rate issuch that when the rail ends make contact and start heating up. flashingwill take place and a certain portion of each of the adjacent rail endsburn oiI without sticking. It will be understood that this rate ofmovement of the platen must necessarily be a slow rate for, otherwise,the rail ends would stick, thus extinguishing the flash and making itnecessary to separate the rail ends and then feed them together again.However, after the rail ends have heated up, and a certain amount offlashing has occurred, it is then desirable to feed the rails togetherat a faster rate because the arc will now sustain more rapid fiashing.Therefore, as fully stated in the introduction hereto, it was heretoforethe practice to cause the platen to trip a limit switch after it hadtraversed a predetertrol mechanism, such as that shown in the abovementioned patent, which would admit more fiuid pressure behind the shaft(5 ami thus increase the rate of .speed of the platen. After the platmhad traversed a predetermined distance at this increased rate of speed,it t pped another limit switch which caused still more fluid mire to beapplied behind the platen, and thus efiect the push-up, which actuallyformed the weld by squeezing out the molten metal.

The problem which this invention seeks to solve becomes apparent fromthe above dscription of the practice heretofore Referring to thedrawing, let us assume that heret0- fore movement of the platen fromdotted-line position A to dotted-line position C was the total movementof the platen until it tripped the first limit switch for the firstincrease in speed. 01 the distance A to C, which the plate: traverseduntil it met the limit switch. the distance A to B represented theseparation of the rail ends, i. e., the distance which the platentraversed before the rail ends engaged andflashing began. Only thedistance B to C represented the efieetive movement of the platen fromthe time the rail ends engaged, and therefore. represented the amount ofburn-oil of the mil mds betore the speed of the platen Wu increucd. If,instead of being separated the distance A-B, the rail ends wereinitially separated a lesser d'mhnce, then it will be seen that flashingwouhlstnrt earlier than inthecasewheretherailendsareinit'nlbseparated'AB, and by the time the platenhas traveled the distance A-C, me of the rail endsthanB-Cwillhavebembumcdofl. Aslresult. when the push-up occurs, it willbe found thatmoremetalwillbeatmdedtlnnwmld bethecaseiftherailendsweresepantcdthedistance 11-13. On the other hand,muse the rail ends were separated more than the distance A -B. Then itwill be seen that by the time the platen has traveled the d'ntance 11-0to the first limit switch, a lesser amount than BCof therailendswillhavebcenhurnedofl, and, as a result, when the final push-upoccurs, there will be obtained a weld with les atrusion than in theother two oasesdmihcd. This nonuniformity of welds will result, if thetails are not initially separated a constant distance, such, as,

mined distance, and this limit switch would confor instance, thedistance A-B. In the introduction hereto, it has hem fully uphined whyin the case of heavy objects slmh ls rails moving continually through a.welding mmhine, it is not possible either to stop the last rail with itsend l9, or to stop the nextrnilwith its adjacent end 20, in any fixedrelative position, and it was explained why this distance betweenadjacent ends I! and 20 will vary. Thus the problem of non-uniform weldsarises.

In order that a. imiform amount of burmofi of adjacent railendsmay beobtlinciregzrdless of the initial separation of adjacent emk I! and20,1pr0DOSe tooperatethelimitswitchnotby the absolute movement of thephten from A to C. but rather by the movement of the platen after therail ends have come into flashing engagement. Since the point offlashing eat is constant, it ofi'ers a constant zero point from which topredetermine the amount of burn-01!. Thus, if itis desiredtoefiectincruseinfecding rate of the platen ll afteranamormtot bnrnoilequivalent to 13-0 has been eflcctcd, I came the efiective movement ofthe platen for the purpose of actuatingthelimitswitdrtobegmwhen the railends contact, and to cmtinne for the predetermined distance B-C. Thus Ieliminate the variable initial distances between adjacent ends it and 20from the determination of the amount of burn-oft.

To accomplish the above purpose, I provide the following mechanism whichis merely illustrative as one specific embodiment thereof, but anyequivalent structure which will accomplish the fundamental step ofcausing the movement of the platen to become effective to actuate thelimit switches only when flashing engagement takes place, iscontemplated by this invention. In .the form shown, the limit switch maycomprise a rotatable disc "normally held in initial Desi-- tion with itsstop 4| against a fixed stop 42 on the fixed member ill by means of aspring 43. The disc 40 carries one element 45 of a pair of switchcontacts, the other elements 46 and 41 being carried by the fixed memberat predetermined angular distances spaced from switch contact 45. Itwillthusbe seen that if the disc 40 is rotated through a predeterminedangular distance, contact 45 will engage contact '88 to operate thefirst increase of speed in any well known manner, and that after thedisc 40 has rotated through a further predetermined angular distance,contact 45 will engage contact 41 to effect the next increase in speed,or push-up. By.

this invention, I cause the disc 40 to begin to rotate not when theplaten ll starts from its original position A, but rather when the railends I9 and 20 come into flashing engagement. For I this purpose, I mayconnect in parallel with the transformer T, a relay 50. Normally, beforethe rail ends engage, the circuit is open and the voltage across theseends is high, and therefore a relatively high current passes through thereand operation of my invention, together with the apparatus which I nowconsider to represent the best embodiment thereof, but I desire to haveit understood that the apparatus shown is only illustrative and that theinvention can be carried out by other equivalent means. Also, while itis designedto usethe various features and elements in the combinationand relations described, some of these may be altered and others omittedwithout interfering with the more general results outlined, and theinvention extends to such use.

Having described my invention, what I claim and desire to secure byLetters Patent is: 1

1. In a rail weldingmachine having a fixed part and a movable platenadapted, respectively, to support two members to be welded, means formoving the platen at a predetermined rate toward said fixed part toeffect flashing engagement of said members, means for changing thespeed'of movement of said platen, means whereby said speed-changingmeans is rendered effective after a predetermined amount of effectivemovement of the platen and means whereby said effective movement iscaused to commence when said members engage.

2. In a rail welding machine having a fixed part and a movable platenadapted, respectively, to support two members to be welded, the platenbeing adapted to move at a'plurality of successively changing speeds asdetermined by a limit switch adapted to be operated by the platen in thecourse of its movement, said switch being adapted to beoperated afterthe ends of said lay coil 5!. As soon, however, asthe rail ends engage,there is a rush. of current through the rail with a resultant drop ofvoltage through coil 5|, causing an armature 52 to be released by meansof spring 63, and breaking contact at 54. The

' contacts 54 are in the circuit or a coil 55 which coil normallyattracts its armature 56 to unclutch a clutch 51 between shaft 8|,carrying the disc 40, and-shaft 82, carrying a pinion 58 which isadapted to be operated by a rack 59 carried by the platen II; Thede-energization of coil 55 permits a spring 80 to render the clutch 51effective, and thus clutch shaft N to the shaft 62 of pinion 58. Fromthis point on, movement of the platen -H will rotate disc 40, but itwill be seen that the rotation of disc begins only when clutch 51 isrendered eifective, which is the time 'when coil 55 is de-energized byreason of the dropping voltage through coil Bl caused by the flashingengagement of rail ends l9 and 20.

While I have disclosed my invention in connection with a machine whereinthe various speeds are in each case increasing speeds, it will beapparent that the invention applies equally well to the control ofdecreasing speeds. In other words, it applies generally for the controlof variable speed feeds.

In accordance with the provisions of the patent statutes, I have hereindescribed the principle members have engaged and predetermined portionsof said members have burned away, said machine characterized by meansfor insuring operation of said switch after constant portions of saidmembers have burned away, regardless of the variations in distancebetween the adjacent ends of said members when the platen starts itsmovement, said means comprising means whereby the travel of said platenis normally ineffective to actuate said limit switch, and means wherebythe engagement of said members renders said platen effective to actuatesaid switch.

3. In a rail welding machine having a fixed part and a movable platenadapted, respectively,

being adapted to move at a plurality of successively changing speeds asdetermined by a, limit switch adapted to be operated by the platen inthe course of its movement, said switch being adapted to be operatedafter the ends of said members have engaged and predetermined portionsof said members have been burned away, they method for insuringoperation of said switch after constant portions of said members haveburned away regardless of the variations in distance between theadjacent ends of said members when the platen starts its movement,which, consists in setting the beginning or effective move ment of theplaten for the purpose of actuating.

said switch from the time the said members GEORGE LESTER JONES.

